Lawmakers routinely referenced terrorist attacks in Orlando and San Bernardino throughout the corresponding state Senate and Assembly floor sessions as the reasons to support and deny the firearms proposals.

Despite claims from Republicans that the gun-control proposals were unconstitutional and “trampled on the people’s will,” the Democratic-led statehouse advanced the sweeping proposals to Gov. Jerry Brown for final approval.

The fiercest debate centered on state Senate President Pro Tem Kevin De Leon’s plan to implement background checks for ammunition purchases, Senate Bill 1235. De Leon’s proposal features similar provisions included in Lt. Gov. Gavin Newsom’s initiative, which has already qualified for the November ballot.

In recent weeks the Senate leader has urged Newsom to remove or amend his initiative, claiming that the Legislature is better suited to craft and approve stringent gun-control measures than voters are.

In an unusual and shrewd political maneuver, De Leon amended SB 1235 to ensure that if both of the competing measures are enacted, De Leon’s program for ammunition background checks would become law instead of Newsom’s initiative.

Last week, Newsom’s camp called the amendments “sickeningly cynical” and vowed to continue pushing the initiative to voters. In an ironic twist, Assembly Republicans on Thursday echoed the liberal lieutenant governor’s concerns over De Leon’s amendments that would overrule sections of his competing initiative.

“Don’t we have a constitutional or statutory problem in amending something that hasn’t even become law yet and is proposed to go to voters for a vote?” Assemblyman James Gallagher (R-Plumas Lake) asked.

The bill’s co-author, Assemblyman Kevin McCarty (D-Sacramento) said the bill will help prevent felons from easily purchasing ammunition and that he helped enact a similar program 10 years ago while on the Sacramento City Council. Republicans countered by noting that a federal background check program for ammunition failed decades ago, and that criminals will always find ways to circumvent gun-control laws.

“I know for a fact ISIS is not going to be going through having their information registered by the department,” said Assemblywoman Marie Waldron (R-Escondido).

Assembly Republicans unsuccessfully motioned the Assembly chair to delay a vote on SB 1235, and it eventually passed 44-29.

De Leon’s proposal requires individuals to show identification when buying ammunition, and vendors to verify the identification through a California Department of Justice database to ensure buyers aren’t on the prohibited list. Similar programs are in place in cities across the state, including Sacramento.

The program will be funded through a $1 fee on ammunition transactions, and retailers without internet access can verify identifications through a Department of Justice hotline.

De Leon passed a similar bill in 2009 but it was held up in the courts and eventually deemed too vague by a judge.

The Assembly passed a measure requiring gun owners to report stolen firearms within five days of the theft or face fines up to $1,000. A measure increasing the state’s assault weapons ban to include guns with “bullet buttons” also cleared the Assembly.

Meanwhile, the state Senate approved a measure limiting Californians’ purchases of long guns and rifles to one per month, and a bill making it a misdemeanor to falsely report a gun as stolen.

A bill to allow individuals to petition a court for a restraining order to bar a co-worker from owning a gun was also approved. Assembly Bill 2607 mandates courts to hold a hearing on a requested petition within three weeks. Currently law enforcement and family members can ask the court to bar someone from owning a gun.

In total, 13 firearm bills were sent to Brown for final approval. Several of the approved measures have been vetoed by the Democratic governor in the past.

Brown told the Sacramento Bee in an interview that he will “take mixed action” on the gun-control bills and act on them before he leaves today for a two-week European vacation.

A Quinnipiac University poll released Thursday found overwhelming nationwide support for stricter gun-control bills and background checks for firearm purchases. Registered voters surveyed supported tougher gun-control laws 54 percent to 42 percent, the highest level of support in the poll’s history.

De Leon said once signed by Brown, the proposals will be a “beacon of hope for the rest of the nation to follow.”